We are currently seeking candidates for the following thesis project to be conducted at the Laboratoire de Géologie de Lyon : Terre, Planètes, Environnement.
Climatic, environmental changes and human impacts in Central Africa over the last 28 ka inferred from organic biomarkers
Supervisors: Guillemette Ménot, Matthew Makou
Project Enquiries: guillemette.menot@ens-lyon.fr, matthew.makou@univ-lyon1.fr
Understanding and forecasting climate variability is a major scientific challenge, particularly in Africa, which has been recognized by the IPCC as one of the most vulnerable continents to climate change. Of key interest is how temperatures, rainfall, and fire activity will evolve with increasing greenhouse gas concentrations. From this point of view, reconstructing the abrupt climatic and environmental events that have punctuated the recent history of the African continent is of prime interest to better understand the response of African climate and ecosystems to both external forcing and internal feedbacks. Past studies have shown that African climate, in particular the monsoon, can respond rapidly to gradual insolation changes. However, many issues remain unresolved, such as the timing and spatial expression of major past perturbations associated with the deglaciation and African Humid Period.
The aim of this PhD research is to employ the organic matter preserved in a sediment core from Lake Barombi in Cameroon to characterize and quantify climatic changes and anthropogenic impacts over the last 28 ka, notably concerning temperature, precipitation, and fire activity. This core represents one of the few sedimentary archives on the African continent covering the deglaciation and the Holocene. The candidate will work to characterize the sediments and then develop stratigraphic records based on an extensive organic geochemical toolbox, potentially including: glycerol dialkyl glycerol tetraethers (GDGTs) and compound-specific δD for quantitative assessment of continental temperatures and precipitation, respectively, levoglucosan as a proxy of past fire dynamics, and coprostanol as an indicator of human presence. The research will include organic geochemistry laboratory work, possibly fieldwork (depending on the candidate), and frequent interactions with researchers from other institutions (sedimentologists, mineral geochemists, and archeologists) involved in this interdisciplinary project.
This PhD project would suit a quantitative geoscientist with a solid geochemistry background, or a student from a chemistry background with a strong interest in paleoclimatology or geology, who is keen to develop laboratory skills. The candidate will reside and conduct research in Lyon, France, and all work related to the thesis can be conducted in either French or English.